Apparatus for surface-finishing articles



May 14, 1968 c. J- A. KELLARD APPARATUS FOR SURFAGEFINISHING ARTICLES Filed May 5. 1965 M t d M E r I, o

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a a H 1%? mw mm NGQ m m I m l mm m. mm D I Ml l w w v mm N mm mm vw t K 1 A 5 a 51 i qlp flwhfi r mm w I T i l l I I IHTUMHH l i fi l hwl l H H H W UMP 1 ii, UL H. l l l l l [1L 1 m R m m m A'r oEuEv United States Patent 3,382,621 APFE'ARATUS FOR SURFACE-FINISHING ARTHCLES Charles J. A. Kellard, Stevenage, England, assignor to Mechanical Handling Plant and Construction Company Limited, Knebworth, England, a British company Filed May 3, 1965, Ser. No. 452,535 11 Claims. (Cl. 51-7) ABSTRACT OF THE DISCLOSURE A surface-finishing machine, especially for long articles. A trough has a resilient base formed by a horizontal flexible sheet separating the trough from a water-filled region. The article is reciprocated in finishing medium laid in the trough by a movable carriage, which can also extract the medium to a desired level to expose the article for removal.

This invention relates to the surface-finishing of articles, and more particularly to the surface-finishing of articles by agitating them in contact with a finishing medium comprising a bed of granules permeated by a liquid, with which abrasive particles may be mixed.

It is an object of the invention to provide an apparatus which enables long articles to be surface-finished in a uniform manner along their length, and apparatus in which such a process can be carried out.

The apparatus according to the invention comprises means for submerging the article in a horizontal bed of granules which is resiliently supported on a horizontal base and which is permeated by a liquid, means for reciprocating the article in a horizontal direction until the finishing action of the bed has reduced surface roughnesses on the article to a desired smoothness, means for draining the liquid from the bed at least to a level below the article, and means for removing the granules above the article.

A plurality of articles may be surface-finished simultaneously by being clamped to a common frame which is itself reciprocated. Also, the granules removed from above the article may be replaced on top of subsequent articles to allow a plurality of articles to be surface-finished in succession.

The granules may be removed and replaced by means carried by a mobile body arranged to move horizontally above the bed.

The resilient base is preferably a fluid cushion comprising a closed fluid-filled tank whose upper wall is a resilient sheet.

Apparatus constructed in accordance with the invention for surface-finishing an article will now be described in greater detail by way of example with reference to the accompanying drawings, in which:

FIGURE 1 is a plan view of the apparatus;

FIGURE 2 is a transverse section on the line II--II of FIGURE 1, and

FIGURE 3 is a side view of the apparatus of FIG- URE 1.

Referring to the drawings, the apparatus for surfacefinishing an article comprises essentially a finishing table 1 and a mobile carriage 2.

The finishing table 1 has a lower part formed by two side members 3a and two end members 3b, and an upper part formed by two side members 4a and two end members 4b. The members 3a, 3b, 4a and 4b are flanged at top and bottom, and the lower members 3a and 3b are bolted to a base plate 5 which is carried by a support frame 6. The width between the side members 4a is the same as that between the side members 3a, on which they rest, but the side members 4a are longer than the side members 3a, so that the upper part projects beyond the lower part at the ends of the table 1. Two members 7, similar to the end members 4!), cross the upper part of the table 1, and are positioned above the end members 3.5. A resilient diaphragm 8, made for example of rubber, is stretched between the upper and lower part of the table 1, and is clamped at its edges between the side pieces 3 and 4, lower members 3a and 3b and the side members 411 and the cross members 7. The lower part forms a closed tank whose upper boundary is the resilient diaphragm 8 and the upper part thus forms a trough whose base is this tank. Before operation of the machine, water is introduced into this tank through a supply pipe 9, air being allowed to escape through an air vent 19, until the tank is completely filled with water. As an alternative to water, compressed air may be used. A further pair of base plates 11 and 12 are bolted beneath the projecting ends of the upper side pieces 4.

A number of bushes 13 are attached to the two longitudinal side pieces 4, and through them pass two rods 14, one on each side of the trough. Two cross-pieces 15, one at each end of the table 1, are clamped to the rods 14 to link them together.

A hydraulic cylinder 16 is mounted on one end of the table and is fitted with a piston on the end of a ram attached to the underside of the adjacent cross-piece 15. A source 17 of fluid under pressure is connected by conduits to a control valve 18 which connects one side of the piston of the cylinder 16 to the source, and, depending on its position, the other side of the piston either to the source or to the reservoir from which the source withdraws fluid. This side is of smaller area than the first side, and as a result the piston either advances or withdraws. The position of the control valve 18 is tripped by a lever on the cross-piece on passage of the crosspiece over it, so that the piston, and the frame connected to it, reciprocate back and forth. The apparatus can be in continuous use for considerable periods of time, and as this could give rise to overheating of the fluid, a heatexehanger is provided to cool the fluid. A particularly simple form of heat-exchanger is achieved by passing the conduits connecting the valve 18 to the cylinder 16 through the tank formed by the lower part of the table in a heat exchanging section 19 formed by passing the conduit back and forth across the tank. The reciprocating device described could be replaced by any other suitable device, for example, one operated pneumatically.

The article 20 to be finished is clamped at each end to an anchor member 21. Each anchor member 21 is arranged across the table 1 and is clamped at both ends to the rods 14, for example by each rod 14 being held between the anchor member 21 and a plate 22 bolted to it. The anchor members 21 are bent near their ends so that their middle parts are at a lower level than the rods 14. The article 20 is clamped at each end to these middle parts of the anchor members 21, for example by being held between pairs of clamp plates 23 each of which is either bolted to its anchor member 21 or passes on either side of its anchor member 21 and is held together by a bolt passing between the anchor member 21 and the article 29.

Liquid, for example, water can be introduced into the trough formed by the upper part of the table 1 by inlets 24 fed by a supply pipe 25. A pipe 26 opens through the base plate 11 into this trough and is closed by a bung which, when removed, allows liquid to drain from the t ough. A similar pipe 27 opens through the base plate 12.

The table 1 is conveniently situated in a recess in the floor with a gulley passing beneath it into which discharged liquid can drain.

The mobile carriage 2 runs on a track 2?: which passes in either side of the table, its rails being situated at the edge of the recess in the floor if there is such a recess. The carriage 2 has a stout framework 29 which spans the table and carries a hopper 39 which tapers. downwardly to a bottom edge that is at a height just sufiicent to clear the table 1. The hopper 3i carries granules which can be released through a door 31 situated at the bottom of the hopper Ell. The door 31 can be opened by a handle 32 to a controlled extent.

Four pipes 33, which remove granules from the trough, open into the upper part of the hopper 38. Each pipe 33 ends in an extractor mouth 34; the thickness of these mouths 34- are reduced relative to the pipes 33 in the direction longitudinal to the table 1 and are widened in the direction transverse to it, and the extractor mouths 3d abut one another side by side so that there is effectively formed a narrow slot extending across the width of the table 1. Each of the extractor mouths 34 is connccted to its pipe 33 by a sliding joint 35 which allows the height of the extractor mouths 34 to be adjusted.

A pump unit 36, comprising an extractor fan and an electric motor to operate it, is carried on the top of the framework 29 and arranged, when operating, to extract air from the interior of the hopper 3d.

The carriage 2 is powered by an electric motor 37 which is carried on the framework 29- and which drives one of the wheels of the carriage 2 through a chain drive.

In operation of the apparatus, the tank below the diaphragm 8 is filled with water, and a lower layer of granules is layed on the diaphragm 8 by traversing the carriage 2 along the table with the door 31 open. The granules are of a kind suitable for use in finishing machines, for example, chips of ceramic material or aluminous oxide. The rate at which the carriage lays granules de pends on the extent to which the door 31 is open and the speed at which the carriage moves; it may be necessary to make more than one traverse to lay a layer of the desired height. The article to be finished, which may for example be a milled article having burrs or other surface roughnesses it is desired to remove, is then placed on the layer of granules and clamped to the anchor members 21 by the clamp plates 23. If necessary, the distance apart of the anchor members 21 is adjusted to fit the article 29 to be finished, by loosening the clamps 22 of one of the anchor members and sliding it along the rods 14. If the article 2 3 does not extend along the whole length of the table 1, other articles can be clamped to further anchor members 15 inserted between the rods 14, and the machine then finishes a plurality of articles simultaneously. The height of the lower layer of granules is made such that, when the article 20- is clamped, the resilient diaphragm 8 is just distorted; this ensures that the granules are held in contact with the article 20.

An upper layer of granules is then layed by traversing the carriage 2 along the table. This layer is of a sufiicient depth to submerge the article 2% in the bed 38 of granules formed, but it is not so deep as to submerge the rods 14- and cross-pieces 15. The shaping of the anchor members 21 allows the article 20 to be submerged in the bed without the remainder of the frame being also submerged, which would result in undesirable wear.

The bed is then permeated by liquid, which may, depending on the desired finish, have a suspension of abrasive powder mixed with it. Thus, water may be introduced through the inlets 2d to a level equal to the top of the bed 38 and abrasive powder or finishing compound added by hand. The source 17 of liquid under pressure is then switched on, which causes the cylinder 16 to reciprocate, reciprocating the frame comprising the rods 14 and cross-pieces 15 and the article or articles clamped to them. The initial effect of the movement of the article is to mix the water and abrasive powder or finishing compound together and with the bed of granules 38, and the finishing medium thus formed then acts on the article or articles being finished to remove or reduce the surface roughnesses or other imperfections prescut.

The bed of granules 33 is retained by the members 7 each of which is provided with two openings each covered by a trap 39 which can be lifted to allow water to pass under the member 7; the openings may be covered by a perforated plate to prevent escape of the gran ules with the water.

Vertical baffles ll) are arranged transversely in the lower tank to damp the surging of the water in this tank which would otherwise result from the reciprocatory motion of the article Ztl. They extend to a height just below the maximum expected distortion of the diaphragm 8 and are provided with apertures at their base to allow water to pass from one end of the tank to the other for filling or draining.

When the article or articles reach a desired smoothness, the source 17 of liquid under pressure is stopped. The traps 39 and the bungs in the drain pipes 25 and 27 are then removed, and all the liquid in the trough allowed to drain away, taking with it at any rate most of the abrasive powder or finishing compound. The pump unit 36 of the carriage 2 is operated, and, with the door 31 shut, the pressure in the hopper 36 is reduced, and air is extracted into the pipes 33. The carriage is then moved to a position above one end of the bed 38 and extractor mouths 34 lowered into juxtaposition with the top of the bed. The extractor mouths are capable of removing granules lying in a layer of a certain depth below the top of the bed, and the carriage is moved along the bed until the whole of this layer is removed. The granules, extracted into the hopper 30, fall to the bottom of it ready to be released through the door 31. If the layer removed is not deep enough to expose the top of the article 20 completely, the carriage 2 is retraversed until all the granules above the article 20 have been removed. The article is then itself unclamped. This leaves a lower layer of granules, and the procedure can be repeated, starting at the point where the article is laid on the lower layer of granules, to surface finish a plurality of articles in succession. The granules which the carriage 2 lays on top of the succeeding articles are thus the granules which the carriage has removed from previous articles.

As all the sections of the article ill in a direction along the table I exist in similar environments, the finishing action is uniform along the length of the article. This would not be the case, for example, if the article were arranged vertically, when the lower parts would be subjected to a more intense finishing action.

The resilient base to the trough forms a cushion which prevents any undesirable scoring in the lower surface of the article, such as would occur with a solid base. The intensity of the finishing action can be determined on the underside by the extent to which the diaphragm 8 is distorted and on the upper side by the weight of the layer of granules above it. It is thus possible to adjust the finishing action on the twosides to an equal intensity.

I claim:

1. Apparatus for surface-finishing an article, which comprises a trough having a resilient horizontal base, a frame slidably mounted on said trough for sliding in a horizontal direction, clamping means on said frame adapted to clamp an article, means for forming a bed of granules in said trough, reciprocatory means for reciprocating said frame in said horizontal direction, a closable outlet of said trough below the level at which the article is adapted to be clamped to drain liquid therefrom, and means for removing a layer of granules of a predetermined depth from the top of said bed.

2. Apparatus as claimed in claim 1, in which the said reciprocatory means comprise a ram attached to said frame, a source of fluid under pressure, conduit means coupling said ram to said source and control means situated in said conduit means operated by movement of said frame and arranged to so connect the said source to the said ram as to cause the said ram to successively advance and withdraw.

3. Apparatus as claimed in claim 1, in which said frame is adapted to receive a plurality of clamping means for clamping a plurality of articles.

4. Apparatus as claimed in claim 1, in which the said resilient base is a resilient sheet forming the upper boundary of a sealed region containing fiuid.

5. Apparatus as claimed in claim 4, in which the said fluid is water and there are provided bafi'le means in said region for at least hindering oscillation of said water in said direction.

6. Apparatus as claimed in claim 4, in which the said fluid is compressed air.

7. Apparatus for surface-finishing an article, which comprises a trough, a horizontal flexible sheet forming the base of said trough, a closed water-filled tank, the said sheet being the upper wall of said tank, a frame slidably mounted on said trough for motion in a horizontal direction relative thereto, clamping means on said frame adapted to clamp an article thereto, means for forming a bed of granules in said trough, a source of fluid under pressure, a ram attached to said frame, conduit means coupling said ram to said source, control means situated in said conduit means and operated by movement of said frame to so couple said ram to said source as to cause said ram to successively advance and withdraw, the said frame thereby being reciprocated, the said conduit means passing in heat-exchanging relationship with said water-filled tank, a closa'nle outlet to said trough below the level at which said article is adapted to be clamped to drain liquid therefrom, and means for removing a layer of granules of a predetermined depth from the top of said bed.

8. Apparatus for surface-finishing a plurality of articles, which comprises a trough having a resilient base, a frame slidably mounted in said trough for sliding in a horizontal direction, releasable clamping means on said frame adapted to clamp an article, reciprocatory means for reciprocating said frame in said horizontal direction, an outlet to said trough to permit liquid to drain therefrom situated below said position in which said article is clamped, a body mounted for horizontal motion above said trough, means carried by said body for laying a bed of granules in said trough, and means carried by said body for extracting a layer of granules of a predetermined depth from the top of said bed.

9. Apparatus for surface-finishing a plurality of articles, which comprises a trough having a resilient base, a frame slidably mounted in said trough for sliding in a horizontal direction, releasable clamping means on said frame adapted to clamp an article in a position above said resilient base, reciprocatory means for reciprocating said frame in said horizontal direction, an outlet to said trough to permit liquid to drain therefrom situated below said position in which said article is clamped, a hopper mounted for horizontal motion above said trough, a

closable outlet from said hopper adapted when open to release a layer of granules contained in said hopper into said trough on horizontal motion of said hopper above said trough, conduit means communicating with the interior of said hopper, a vertically movable extractor mouth to said conduit means, and pump means adapted to remove air from said hopper when said outlet is closed and said extractor mouth is in juxtaposition with the top of a layer of granules in said trough to thereby extract into said hopper a layer of granules.

10. Apparatus for surface-finishing an article which comprises a trough having a resilient horizontal base, a bed of granules situated in said trough and permeated by a liquid, a frame slidably mounted on said trough for sliding in a horizontal direction, an article clamped to said frame and submerged in said bed, reciprocatory means for reciprocating said frame in said horizontal direction, an outlet situated in said trough below said article to permit the said liquid to drain therefrom, and means for removing those of said granules situated above said article.

11. Apparatus for surface-finishing an article, which comprises a trough, a horizontal flexible sheet stretched across said trough adjacent to the base thereof, the region beneath said sheet being sealed and filled with water, a bed of granules permeated by liquid, supported on the said sheet, a frame comprising two parallel horizontal rods and a cross-piece, one rod being slidably mounted on each side of the trough and the cross-piece coupling the said two rods rigidly together, the said parts of the frame being situated above the said bed, at least a pair of anchor members each secured between the said two rods, an article clamped to said pair of anchor members, the said article being submerged in the said bed, an outlet to permit liquid to drain from said bed, said outlet being situated below said article, a hopper mounted astride said trough on rails running the length of said trough one on either side thereof, a closable outlet from said hopper adapted when open to release a layer of granules contained in said hopper into said trough on horizontal motion of said hopper above said trough, conduit means having at least one extractor mouth, the extractor mouth being vertically movable into juxtaposition with top of said bed, and pump means adapted to remove air from said hopper when said outlet is closed and said extractor mouth is in juxaposition with the top of said bed to thereby extract into said hopper granules from the top of said bed.

References Cited UNITED STATES PATENTS 1,076,636 10/1913 Keil 517 X 3,128,577 4/1964 Guibert et al. 51-7 3,248,826 5/1966 Van Fossen 517 X LESTER M. SWINGLE, Primary Examiner. 

